The invention relates to production of crude oil from subterranean oil bearing formations and, more particularly, to an improved system, method and apparatus for mixing treatment fluids with the crude oil to improve production of the crude oil to the surface.
Various methods and systems are known for mixing diluent and other treatment fluids with a crude oil being produced so as to reduce the viscosity of the oil and thereby improve production.
Prior Art FIG. 1 shows a typical conventional system whereby diluent is pumped into the annular space of the well and mixes in the production zone with oil being produced. With this system, however, the column of diluent in the annular space exerts a pressure on the producing formation which reduces production and which can result in escape of the diluent into the formation.
Prior Art FIG. 2 illustrates another known arrangement wherein the treatment fluid is introduced through the production tube and is mixed with pumped crude oil in the production tube. The mixture then enters and is produced through the annular space through a perforated nipple located above the pump. With this arrangement, the treatment fluid does not pass through the pump which is therefore subjected to increased wear due to its operation on the highly viscous crude oil. Further, treatment fluids designed to treat the pump specifically, such as anticorrosive fluids, cannot be used.
Prior Art FIG. 3 illustrates another known arrangement wherein treatment fluid is pumped down the annular space and is metered directly into the pumping unit by a check valve. With this system, however, the check valve is frequently plugged by solids in the treatment fluid stream.
Prior Art FIG. 4 illustrates a similar approach to FIG. 3 wherein the plugging problem is addressed. However, in both of FIGS. 3 and 4, the diluent or other treatment fluid is introduced directly into the pumping chamber and, therefore, the mixture of crude oil and diluent is not homogeneous. Thus, the pump is still subjected to increased wear due to the existence of non-mixed slugs of highly viscous crude oil.
It is therefore the principal object of the present invention to provide an improved system for treating crude oil being pumped from a subterranean oil bearing formation.
It is a further object of the invention to provide a system wherein treatment fluids are mixed substantially homogeneously with crude oil to be produced before the mixture enters pumping equipment.
It is a still further object of the invention to provide such a system wherein treatment fluids are drawn through the pumping equipment.
It is another object of the invention to provide such a system wherein treatment fluids are not lost into the producing formation.
Other objects and advantages will appear hereinbelow.